Governor valve mechanism



Feb.16,1943. @.LUTHERER y 2,311,061-

GOVRNOR VALVE MECHANISM Filed. July 5, 1939 Patented Feb. 16, 1943 UNiTED STATES PATENT orsi-cn GOVERNOR VALVE MECHANISM Y om Lutherer, s111011', chip, assigner im` 'rhe Noren American Manufacturing Company, Cleveland, Chio, a corporation of Ohio Application July 3, 1939, Serial No. 282,637

4 Claims.

This invention relates to Valve mechanism for controlling the iiow of fuel gas to gas burners, and more particularly relates to a shut-off attachment for zero pressure control Valve mechanism.

In the supply of fuel gas to burners the gas is` frequently supplied at zero or atmospheric pressure by means of a zero pressure governor valve. One difficulty with such governors has been that when the supply of air under pressure to the burner is abnormally reduced or is cut off, the Zero gov' ernor valve does not completely close, or at best, it-is held to its seat by zero pressure. Consequently any slight variation in pressure, such as by increase in suction produced by the Venturi or inspiration effect at the burner, is likely to produce gas leakage through the Valve, with enough gas flowing either to overshoot the temperature to be attained or to make the operation hazardous, as-with unred semior full muffled furnaces.

One object of the invention is to provide improved valve mechanism for use in connection with Zero pressure governor devices, Iand in which mechanism, when the air supply is vabnormally reduced or is cut off or fails, the gas governor Valve is held to its seat by positive pressure sufcient to prevent any leakage or escape of gasV through the valve, and in which, during normal operation, with theair pressure turned on, the

said positive holding pressure is completely eliminated or is made non-effective, so that it exerts` no influence upon theusual pressure governing functions or operations of the controlling valve mechanism'.

A further object of theinvention is to provid an' arrangement of this kind which is automaticl in operation, requiring no attention whatever` from the operator, but which nevertheless is reliable and dependable for the performance of its duty under al1 conditions.

A further object of the invention is to provide' ply thereto, the valvefmechanism being showin in sectional elevation; f

Fig. 2 is a detail View, corresponding to Fig. 1, and illustrating a modification.

shown, described and claimed in-'a prior application Serial No. 264,410 forvGas ra'nd'air mixer -for burner, iiled March 2'?,l 1939, jointly by myself andr Charles E. Sladky, to whichreferenev may be had' for a more complete description, if desirable ornecessary. The' burner mixer comprises a hollow casing `or body, generally indicated at I', commuv nicating with an air supply pipe 2 and a gas supuply pipe 3. The air is delivered to an oricel,y beyond which the mixture of gas and airiiowsv through the throat 5 to a mixing chamber 6 from which the mixture is supplied to the hollow member 1 forming part of or connected tothe' burner. In burner-s of this kind there is a Venturi effect, with the production by the stream of flow#- ing air of a suction or va'ouurri effect, with a consequent tendenoy to inspirate'or draw' in the gas from the gas supply pipe. The eifect of the mixerl and burner therefore is to reduce the pressure or increase the suction in the gas supp-lypi'pe.l

Referring vto the control Valve mechanism shown in Fig. 1, said mechanism includes a hollowvalve body Ill connected in the gas supply pipe 3 and having supply and' discharge chambersr I I', I2, with the -iiovvA of-gas controlled by a valve VIll carried by a stern I4.

Attached to the top ofthe valvejvbody is a chambered diaphragm casing I5, in which isa movable abutment, such as a diaphragm I6,fas tened to the valve stem and carriedby a support and guide Il fixed to s aid stem and working looselyin an opening in the casing. A diaphragm' I8, the area of which is small and Whoseeffect is therefore negligible, is attached to the valve stem andy seals or closes oil communication from the gas supply chamber I'Iv to the chambers within casing I5. A small opening, such a's'that' through a pipe I9, however, establishes communication from the lower chamber 20 tothe outlet ordischarge' chamber I2 of the valve casing. Y Y

Chamber 2|, above the diaphragm I5, is venited to atmosphere by way of a small port 22,4and in a tubular extension 23 of the diaphragm cas-'- ing is located anadjustablelightloadingtension springll connected at its lower end to the valve stem andat its upper end to a threaded'rod'25v sufficient strength or force'toalmost cxactlysupport the weight" of the movabler parts to whichVA it is attached, including the valve, its stem, and the diaphragms, when the valve is closed upon its seat, and the strength of the spring may be brought to such value by proper adjustment of the nut 25, as will be obvious. When said spring is properly adjusted, therefore, the weight of the valve stem, diaphragms, etc., is eliminated and may be disregarded.

Below the valve, the valve casing supports a suitable servomotor, shown yasincluding a movable differential pressure operated abutment, such as a diaphragm 3|, enclosed within a second hollow casing 30 attached to the main valve casing |5, said diaphragm being attached to a rod or stem 32 passing loosely through a guide 33 and entering the gas outlet chamber 3|. Said rod is free of connection with the valve stem, but lis axially alined therewith and is directly below the same.

The chamber within casing 3|) above the diaphragm 3| communicates either by way of a small port or around the valve stem with the gas outlet chamber I2. The chamber beneath diaphragm 3| communicates by way of a pipe 34 and valve 35 with the air supply pipe 2 on the upstream or supply side of a hand operated controlling valve 35 in said air pipe. Pipe 34 also communicates with atmosphere by way of a bleed cock or valve 31, which normally is left open.

38 indicates conventionally a mechanical connection, such as a link, between the handle of valves 35 and 36 so arranged that said valves always operate in opposition. That is to say, the two valves are operated manually but always conjointly, the arrangement being such that always when valve 35 is open valve 35 is closed, and vice versa.

The valve mechanism described operates as follows:

Air pipe 2 and gas pipe 3 of course individually may be provided with their own main shut-off valves, not shown. Let us assume that said main valves are wide open, with the supplies of both air and gas turned on, that the burner is ignited, and that the system is therefore in normal operation.

Valve 3S, of course, is open, and, consequently, should remain open. Consequently valve 35 is closed. Asy a result, the chamber beneath diaphragm 3| is open to atmosphere through the bleed cock 31. Said diaphragm 3| is therefore subject on its lower surface to atmospheric pressure and upon its upper surface to approximately the same pressure, to-wit, the gas pressure in chamber l2, through which gas is ovving on its way to the burner. kDiaphragm 3| and rod 32 therefore have dropped by their own weight and are in their lowermost position, with the rod 32 entirely out of engagement with and ineffective upon the valve stem. The valve is therefore subject to the inspiration or suction effect at the burner mixer, with gas flowing through the valve to said mixer. The valve operates as a zero pressure governor, and the cross connection between valves 35, 36, with the bleed cock 31, may be regarded as means operatively connected with the supplemental servo motor for positively rendering it ineffective or inoperative when the zero pressure governor valve is operating during normal gas flow. With no flow of gas, valve |3 is closed, and lies in contact with its seat, being held there by spring 24, but without pressure.

Any demand for gas reduces the pressure in the outlet chamber |2, unbalances the forces eiective upon the valve, and opens the valve propor- 75 tionately, with a consequent flow of gas. As the suction effect increases the valve opens wider and wider, and as it is reduced the valve moves toward closed position. But in any event, the gas 5 pressure in chamber |2 is approximately atmospheric, so that diaphragm 3| remains depressed. During normal operation of the valve mechanism therefore, it functions like any ordinary zero pressure governor valve, permitting gas to iiow in accordance with the varying demand of the Venturi nozzle in the mixer.

If the flow of air to the mixer and burner is abnormally reduced, such as by closing valve 36, the same operation, through the mechanism 3B, opens valve 35. Full air pressure, considerably above atmospheric, now becomes effective through the pipe 34 upon the lower face of servo motor diaphragm 3|, the oriiice through the p lbleed port 31 being so small that its venting effeet is negligible. The pressure beneath diaphragm 3| therefore now becomes suiiicient to preponderate over the pressure in chamber |2, so the diaphragm 3| and the rod 32 are elevated. The upper end of said rod engages the valve stem and either closes it upon its seat or holds it to its seat if it is already' there. Therefore, when the air supply is cut olf the former zero pressure governor valve now becomes a shut-01T valve positively held to its seat by the servo motor diaphragm, and more particularly by the preponderating effect thereon of the air pressure in pipe 2 on the inlet side of valve 35. Consequently there is no possibility of escape or leakage of gas through the gas valve such as might overshoot the temperature to be obtained, or entail hazard,

as in the case of muille furnaces.

Fig. 2 illustrates a modification in which the lower servomotor diaphragm 3|a, on its lower face, is subject not to the pressure of the air supplied through pipe 2, but to the pressure of atmosphere by way of a small port 4|), and to the pressure of a compression loading spring 4|, while on its upper face said diaphragm 3|a is subject to the pressure of the air supply pipe, on the downstream side of its main valve (not shown) by way of pipe 42. Connection between the upper chamber 43 of the diaphragm casing and the outlet cham-ber |2 of the valve casing is shut off by a supplemental small sealing diaphragm 44.

With this arrangement, as long as air iiows normally to the mixer and burner through the air supply pipe 2, the pressure within said pipe is effective in chamber 43 and preponderates over air pressure and the effect of spring 4| beneath diaphragm 3|a, thereby positively holding said diaphragm and the rod 32a depressed, or in their ineffective positions. The valve, therefore, functions as a zero pressure governor valve in the same manner as in the form before described.

However, when the air supplyl is cut off, by closure of the main valve (not shown) in pipe 2, or should said air supply fail or should it be otherwise abnormally reduced for any reason independent of operator control of the pipe 2, the compressed air supply through pipe 42 to chamber 43 also fails or is abnormally reduced. As a result servomotor diaphragm 3|a, now is subject on both of its faces to atmospheric pressure and on its lower face also to the effect of loading spring 4|, so that the preponderating pressure is below said diaphragm. It ltherefore either rises and applies the rod 32a to the lower end of the valve stem and closes said valve, or it holds it closed if it is valready closed. Therefore, when there is no air supplied to the burner the valve operates as a positive shut-olf valve for the gas supply, with the positive pressure of the servomotor holding the valve to its seat, as in the first form described.

The arrangement just described, therefore, operates in generally the same manner as the form shown in Fig. 1, but has the added advantage that the valve closes automatically and is held closed, in case of abnormal reduction in or failure of air pressure beyond the knowledge of the operator.

What I claim is:

1. In apparatus for supplying a mixture of gas and air to a burner and including a burner and the gas and air supply pipes therefor, the combination of a zero pressure governing valve in the gas supply pipe arranged upon ow of both gas and air to regulate the gas i'low in accordance with the suction effect of the burner, differential pressure operated movable abutment means so arranged and mounted that when its abutment moves in one direction it closes said valve to positively shut off gas flow and when moved in the opposite direction it releases said valve for free movement, and means associating said abutment means with the air supply pipe in such manner as to move said abutment in the valve releasing direction when normal air flow to the burner is permitted and to move said abutment in the valve closing direction when the air ilovf is abnormally reduced.

2. In apparatus for supplying a mixture of gas and air to a burner and including a burner and the gas and air supply pipes therefor, the combination of a Zero pressure governing valve in the gas supply pipe arranged upon iiow of both gas and air to regulate the gas ow in accordance with the suction effect of the burner, differential pressure operated movable abutment means so arranged and mounted that when its abutment moves in one direction it closes said valve to positively shut off gas ow and when moved in the opposite direction it releases said valve for free movement, means for supplying a substantially constant pressure to one face of said abutment means, and means for applying the pressure of the air supply to the opposite face of the abutment means, said means being so arranged that the abutment is biased in the valve releasing direction when normal air flow is permitted and is biased in the opposite direction when air flow is abnormally reduced.

3. In apparatus for supplying a mixture of gas and air to a burner and including a burner and the gas and air supply pipes therefor, the combination of a zero pressure governing valve in the gas supply pipe arranged upon ilow of both gas and air to regulate the gas flow in accordance with the suction eiect of the burner, differential pressure operated movable abutment means so arranged and mounted that when its abutment moves in one direction it closes said valve to positively shut.v olf gas ilow and when moved in the opposite direction it releases said valve for free movement, said abutment during normal air ow to the burner being sensitive upon its valve releasing face topressure of the gas flowing to the burner and upon its opposite face to a lesser pressure, and means arranged when the air supply to the burner is cut off to apply to said opposite face the pressure of the air supply, whereby during normal air flovr to the burner the valve is fully released and when the air supply to the burner is cut off the valve is positively closed and serves to fully shut off gas flow.

4. In apparatus for supplying a mixture of gas and air to a burner and including a burner and the gas and air supply pipes therefor, the combination of a zero pressure governing valve in the gas supply pipe arranged upon ilow of both gas and air to regulate the gas flow in accordance With the suction effect of the burner, differential pressure operated movable abutment means so arranged and mounted that when its abutment moves in one direction it closes said valve to positively shut oi gas W and when moved in the opposite direction it releases said valve for free movement, said abutment being sensitive upon its valve closing face to the pressures of atmosphere and a spring, and means for applying to its opposite face the pressure of the air flowing to the burner, Whereby during normal air flow tothe burner the valve is fully released and upon abnormal reduction in air flow the valve is positively closed and serves to fully shut off gas flow.

OTTO LUTHERER. 

